Recently, a laser treatment apparatus has been widely used in the field of dental examination. The laser treatment apparatus basically comprises a laser generation apparatus, an optical guiding device for guiding laser beam, a handpiece connected with the tip end of the optical guiding device, and a laser irradiation tip mounted on the tip end of the handpiece. The laser generation apparatus of the laser treatment apparatus can use several kinds of laser generation apparatus for generating laser such as Er:YAG laser, carbon dioxide laser, Nd:YAG laser, semiconductor laser. Er:YAG laser with high absorbability in water has been used these days, wherein a spray mechanism is attached for spraying mixed mist of water and air on a laser irradiation region taking advantage of absorbability in water. The laser treatment apparatus having the spray mechanism of mixed mist of water and air is disclosed in Patent Literatures 1 to 4.
Patent Literature 1 discloses a dental treatment apparatus for removing matter from the surface of teeth by pulsed laser in which a liquid layer of 10 to 100 micrometers in thickness is formed on teeth. Patent Literature 2 discloses a laser treatment apparatus which is provided with a handpiece for irradiating Er:YAG laser and sprays mixed fluid of liquid and gas to a patient to be irradiated with laser from a position behind an output end of laser. Patent Literature 3 discloses a laser treatment apparatus which avoids extra laser absorption by setting timing of spraying mixed mist of water and air at the time of irradiating laser pulse. The paragraph [0004] in Patent Literature 4 discloses an optical cutter (laser treatment apparatus) for irradiating Nd:YAG laser on an affected area in which water and air are mixed in a mixing chamber provided around a fiber conduit pipe for laser irradiation and delivered along the conduit pipe via a mesh screen. Patent Literature 4 discloses that a program is provided for adjusting size and speed of liquid particles in such a manner that electromagnetic energy is absorbed by damp air and/or atomized fluid particles to impart disruptive forces to skin (referring to FIG. 5).
Patent Literature 5 discloses an apparatus for removing dental caries by laser having a delivery device for supplying cooling water to an irradiation area with laser, not for spraying mixed mist of water and air.